In this task, you're given a question, a context passage, and four options which are terms from the passage. After reading a passage, you will get a brief understanding of the terms. Your job is to determine by searching and reading further information of which term you can answer the question. Indicate your choice as 'a', 'b', 'c', or 'd'. If you think more than one option is plausible, choose the more probable option to help you answer the question.

Example Input: Question: How often are new issues of the Canadian Journal of Neurological Sciences published? Passage:Multi-dose versions of the vaccine contain the preservative thiomersal (also known as thimerosal), a mercury compound that prevents contamination when the vial is used repeatedly. Single-dose versions and the live vaccine do not contain this preservative. In the U.S., one dose from a multi-dose vial contains approximately 25 micrograms of mercury, a bit less than a typical tuna fish sandwich. In Canada, different variants contain five and 50 micrograms of thimerosal per dose. The use of thiomersal has been controversial, with claims that it can cause autism and other developmental disorders. The U.S. Institute of Medicine examined these claims and concluded in 2004 that the evidence did not support any link between vaccines and autism. Other reviews came to similar conclusions, with a 2006 review in the Canadian Journal of Neurological Sciences stating that there is no convincing evidence to support the claim that thimerosal has a causal role in autism, and a 2009 review in the journal Clinical Infectious Diseases stating that claims that mercury can cause autism are "biologically implausible". The U.K. National Health Service stated in 2003 that "There is no evidence of long-term adverse effects due to the exposure levels of thiomersal in vaccines." The World Health Organization concluded that there is "no evidence of toxicity in infants, children or adults exposed to thiomersal in vaccines". Indeed, in 2008 a review noted that even though thiomersal was removed from all US childhood vaccines in 2001, this has not changed the number of autism diagnoses, which are still increasing.
 Links: a. Thiomersal and vaccines b. Autism c. Canadian Journal of Neurological Sciences d. National Academy of Medicine
Example Output: c

Example Input: Question: How many cups has the team Franz first played for won? Passage:Franz Burgmeier (born 7 April 1982) is a Liechtenstein retired footballer, who played as a midfielder for Vaduz in the Swiss Super League. Born in Triesen, Burgmeier was a burgeoning footballer and keen skier, until he gave up the latter sport at 16 following a serious injury. Having been a youth player for Triesen, he started his professional career with Vaduz. Burgmeier won several Liechtensteiner Cups with Vaduz, who were promoted to the Swiss Challenge League in 2001, and played in the UEFA Cup. After two unsuccessful attempts to win promotion to the Swiss Super League, Burgmeier left for Aarau in 2005. He spent only one season with Aarau before a move to the previous season's runners-up Basel in 2006. His two seasons with Basel were broken up by a loan spell with Thun, before he moved to England with Darlington in August 2008, where he played for one year.
 Links: a. Swiss Super League b. Swiss Super League c. FC Vaduz d. FC Basel
Example Output: c

Example Input: Question: Was King John IV of Portugal still alive when The Anglo-Maratha wars ended? Passage:The Bombay Presidency was created when the city of Bombay was leased in fee tail to the East India Company by a Royal Charter from the King of England, Charles II, who had in turn acquired it on May 11, 1661, when his marriage treaty with Catherine of Braganza, daughter of King John IV of Portugal, placed the islands of Bombay in possession of the English Empire, as part of Catherine's dowry to Charles. The English East India Company transferred its Western India headquarters from Surat, its first colony in that region, to Bombay in 1687. The Presidency was brought under British Parliament control along with other parts of British India through Pitt's India Act. Major territorial acquisitions were made during the Anglo-Maratha Wars when the whole of the Peshwa's dominions and much of the Gaekwad's sphere of influence were annexed to the Bombay Presidency in different stages till 1818. Aden was annexed in 1839, while Sind was annexed by the Company in 1843 after defeating the Talpur dynasty in the Battle of Hyderabad and it was made a part of the Bombay Presidency.
 Links: a. John IV of Portugal b. English overseas possessions c. List of English monarchs d. John IV of Portugal
Example Output:
a

